JP3424720B2 - Exhaust gas recirculation system for internal combustion engines - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation system for an internal combustion engine, and more particularly to an exhaust gas recirculation system capable of realizing a compact internal combustion engine while preferably performing exhaust gas recirculation. .

[0002]

2. Description of Related Art In recent years, the displacement of internal combustion engines has tended to increase, and the amount of intake air also increases with the increase in this displacement. Therefore, it is abbreviated as intake manifold or intake manifold that is part of the intake system. The intake system members such as the throttle valve, which are integrally mounted, are becoming larger. Furthermore, in order to increase the intake efficiency of the internal combustion engine by the supercharging effect, the surge tank formed as a part of the intake manifold is also becoming larger, which tends to make the intake manifold larger.

When the intake manifold and the throttle valve are increased in size, the weight of the intake manifold is increased, so that the intake manifold needs to be supported. Therefore, normally, a support member is provided between the internal combustion engine body and the intake manifold. Is installed to support the intake manifold.

On the other hand, the exhaust gas discharged from the internal combustion engine contains harmful components such as CO, HC and NOx, and various methods for purifying these components have been researched and developed. These CO, HC and NOx can be purified relatively easily by a three-way catalyst or the like. However,
It is said that it is difficult to purify NOx with a three-way catalyst during operation at a lean air-fuel ratio. Therefore, NOx
With regard to, for example, when the combustion temperature becomes high, NOx is generated a lot, while focusing on the large heat capacity of carbon dioxide, the exhaust gas recirculation in which a part of the exhaust gas containing a large amount of carbon dioxide is circulated to the intake system. Circulation (EGR) is performed to lower the combustion temperature and suppress the generation of NOx. Therefore, a passage (EGR passage) for recirculating exhaust gas is provided between the internal combustion engine body and the intake manifold.

[0005]

By the way, as the intake manifold becomes larger, the entire internal combustion engine becomes larger and the weight of the entire internal combustion engine also increases. Further, when the support member for the intake manifold and the EGR passage are independently provided between the internal combustion engine body and the intake manifold as described above,
The structure of the internal combustion engine is complicated and the weight is further increased. For example, when the internal combustion engine is installed in the engine room of a vehicle, the space occupied by the internal combustion engine is increased and the space of the engine room is narrowed. There is a risk that the sex will deteriorate.

[0006] Normally, an EGR valve that is electrically opened and closed is provided in the EGR passage. Generally, the EGR valve is mounted on an intake manifold that is separated from the internal combustion engine body and has a small thermal effect. There is. However, when the EGR valve is on the intake manifold, the oil mist (lubricant oil) in the blow-by gas supplied into the intake manifold easily enters the EGR valve and is easily polluted, so that the function as the valve is impaired. There are also problems.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to properly recirculate exhaust gas in an internal combustion engine that recirculates exhaust gas and has a large intake manifold. It is an object of the present invention to provide an exhaust gas recirculation device that reduces the size of an internal combustion engine while maintaining the above.

[0008]

In order to achieve the above-mentioned object, in the invention of claim 1, a part of the exhaust gas provided in the main body of the internal combustion engine and derived from the exhaust system of the internal combustion engine is used as the recirculation gas. A recirculation gas outflow portion to be taken out, a recirculation gas inflow portion which is provided in an intake system member of the internal combustion engine and into which the recirculation gas is introduced, and one end of which is connected to the internal combustion engine body including the recirculation gas outflow portion. , An intake system support member having the other end connected to an intake system member of the internal combustion engine including the recirculation gas inflow part, and the recirculation gas being formed in the intake system support member, the recirculation gas outflow part the recycle gas guided to the inlet and a recirculation passage, said recirculation passage recycle gas regulating valve is the recycle gas is its valve port position to adjust the flow rate of the recycle gas from
The recirculation passage is attached so as to be disposed at a position lower than the inflow portion, and at least a portion of the recirculation passage between the recirculation gas inflow portion and the valve port position of the recirculation gas control valve is at least The bottom surface position of the recirculation passage has a passage portion which is set lower than the valve opening position of the recirculation gas control valve.

Therefore, one end of the intake system support member is connected to the internal combustion engine body including the recirculation gas outflow portion, and the other end is connected to the intake system member of the internal combustion engine including the recirculation gas inflow portion. Since the recirculation passage for guiding the recirculation gas from the recirculation gas outflow portion to the recirculation gas inflow portion is provided in the intake system support member, the intake system member of the internal combustion engine can be favorably supported by the internal combustion engine body. At the same time, the recirculated gas, which is a part of the exhaust gas, can be satisfactorily circulated in the intake system of the internal combustion engine to lower the combustion temperature and reduce NOx. At this time, the valve opening position
The flow rate of the recirculation gas is adjusted by the recirculation gas control valve provided in the recirculation passage so as to be located at a position lower than the recirculation gas inflow part. Since there is a passage part lower than the valve position of the recirculation gas control valve in the part between the valve position of the control valve and the recirculation gas, the oil mist in the blow-by gas returned to the intake system is It becomes a drop of lubricating oil on the wall surface and accumulates at the bottom position of the recirculation passage, making it difficult for the oil mist to enter the recirculation gas control valve. Staining due to adhesion is preferably prevented. Further, the oil thus accumulated at the bottom position is returned to the intake system of the internal combustion engine again as oil mist together with the recirculation gas.

In the invention of claim 2, the recirculation gas is
It is characterized in that scan control valve is installed in the middle portion of the recirculation passage. Therefore , the recirculation gas control valve is less susceptible to heat damage to the internal combustion engine, while the recirculation gas recirculates before the temperature of the recirculation gas decreases and the soot in the recirculation gas becomes large. By allowing the gas control valve to pass through, contamination of the recirculation gas control valve due to adhesion of soot or the like to the inner wall of the recirculation gas control valve is preferably prevented. Furthermore, the blow-by gas returned to the intake system contains lubricating oil (oil mist), but this recirculation gas control valve is located away from the intake system, so this oil mist is recirculated gas. It is difficult for the recirculation gas control valve to enter the control valve, and contamination of the recirculation gas control valve due to oil mist is prevented.

[0011]

Further, the invention of claim 3 is characterized in that the recirculation gas regulating valve can regulate the flow rate of the recirculation gas over a wide range. Therefore, if the recirculation gas control valve can adjust the flow rate of the recirculation gas over a wide range, the recirculation gas control valve, especially the valve body is usually contaminated, so that the recirculation gas flow rate can be properly controlled. However, in the exhaust gas recirculation device of the present invention, even if the recirculation gas control valve is large and the recirculation gas flow rate can be adjusted over a wide range, the valve body is contaminated. Good control of the flow rate of the recirculated gas is maintained.

[0013]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of an exhaust gas recirculation device for an internal combustion engine according to the present invention mounted on a vehicle. Hereinafter, the configuration of the exhaust gas recirculation device for the internal combustion engine will be described with reference to FIG.

As the internal combustion engine (hereinafter, simply referred to as engine) 1, for example, a direct injection type in-line 4-cylinder gasoline engine is applied. As shown in the figure, the in-cylinder injection type engine 1 is provided with an intake port 2 corresponding to each cylinder, and each intake port 2 has one end through an intake valve (not shown). And opens toward the combustion chamber 3 and extends vertically inside the cylinder head (internal combustion engine body) 4.

An intake manifold 6 is attached to the central portion 4a of the upper surface of the cylinder head 4 which is open at the other end of each intake port 2. For more information,
In the intake manifold 6, each tip portion 8a of the intake pipe 8 branched so as to correspond to each cylinder communicates with each intake passage 10 formed in the intake pipe 8 and each intake port 2 respectively. Central part 4a of the upper surface of the head 4
Is bound to.

As shown in the figure, in the intake manifold 6, a surge tank 7 that extends substantially perpendicularly to the intake pipe 8, that is, parallel to the longitudinal direction (cylinder row) of the cylinder head 4 and exerts a supercharging effect. Are integrally formed, and in fact, the intake manifold 6 has a shape such that each intake pipe 8 is branched from this surge tank 7. An unillustrated air cleaner or the like is connected to one end of the surge tank 7 via a throttle valve 11. The throttle valve 11 is an intake air amount control valve, and the valve opening degree is changed when the throttle valve 11 is opened and closed by operating an accelerator pedal (not shown), for example. As a result, the amount of air taken into the combustion chamber 3 of each cylinder changes and the output of the engine 1 is adjusted.

Further, inside the cylinder head 4, an exhaust port 12 is provided corresponding to each cylinder, one end of which opens toward the combustion chamber 3 and which extends horizontally toward the side surface of the cylinder head 4. . And each of these exhaust ports 1
An exhaust manifold 14 is connected to a side surface portion 4b of the cylinder head 4 whose other end is open.
Specifically, a tip portion 16a of an exhaust pipe 16 branched so as to correspond to each cylinder of the exhaust manifold 14.
However, the exhaust passages 18 formed in the exhaust pipe 16 and the exhaust ports 12 are respectively connected to the side surface portions 4b of the cylinder head 4.

Reference numeral 19 in the drawing denotes a fuel injection valve. The fuel injection valve 19 is electrically connected to the electronic control unit (ECU) 70. Therefore, when a drive signal is supplied from the ECU 70, the fuel injection valve 19 opens and closes according to the drive signal, As a result, a desired amount of fuel is injected into the combustion chamber 3. As shown in the figure, information from various sensors 72 is input to the ECU 70, so that the fuel injection valve 19 is determined based on the information from the various sensors 72. As the sensor applied at this time, there are an air flow sensor attached to the intake system for detecting the intake air amount, a throttle opening sensor (not shown) for detecting the opening of the throttle valve 11, and the like.

A pair of rocker covers 20, 20 are mounted on the upper part of the cylinder head 4 so as to close the upper opening of the cylinder head 4. The pair of rocker covers 20, 20 mainly serve to prevent the lubricating oil, which circulates inside the engine 1 to cool and lubricate each mechanism such as the cam 30 from scattering to the outside of the engine 1. Have

By the way, normally, the cylinder 3 of the engine 1
Since there is a minute gap between the piston 2 and the piston 34, when the piston 34 rises, a part of the air-fuel mixture in the combustion chamber 3 flows from this gap as so-called blow-by gas through the inside of the crankcase to the cylinder head 4. It leaks into the cylinder head chamber formed between the rocker covers 20. Since a large amount of unburned fuel is contained in the blow-by gas that has leaked into the cylinder head chamber as described above, it is preferable to return the blow-by gas to the intake system.

Therefore, in order to return the blow-by gas to the intake system, at least one rocker cover 20 has a positive crankcase ventilation valve (hereinafter referred to as P for short) which functions as a blow-by gas outlet.
One end of a positive crankcase ventilation pipe (hereinafter abbreviated as PCV pipe) 28 is connected via a CV valve 26. The other end of the PCV pipe 28 is connected to the surge tank 7. As a result, the cylinder head chamber and the surge tank 7 can be communicated with each other, and thus blow-by gas can be circulated to the intake system as indicated by a dashed arrow. The PCV valve 26 is a valve that is opened / closed by negative intake pressure in the surge tank 7 and whose opening changes according to negative intake pressure.

From each of the exhaust ports 12, a part of the exhaust gas is used as a recirculation gas (hereinafter referred to as EGR gas) with the inside of the cylinder head 4 facing the side surface of the cylinder head 4 opposite to the side surface portion 4b. Each internal passage 38 for extraction extends. And each of these internal passages 38
Are combined into a single internal passage 39 in the vicinity of the side surface of the cylinder head 4, and the internal passage 39 is located on the end of the cylinder head 4 in the longitudinal direction of the side surface of the cylinder head 4 (recirculation gas). There is an opening at the outflow portion) 4c.

On the other hand, on the lower surface of the end of the surge tank 7 in the longitudinal direction, that is, on the lower surface position which is in the vicinity of the throttle valve 11 and substantially faces the EGR take-out portion 4c, a projecting portion 40 is provided extending downward. An internal passage 42, which has one end facing the inside of the surge tank 7 and an opening at the other end at the lower surface (recirculation gas inflow portion) 44 of the protrusion, extends vertically inside the protrusion 40. It is provided.

Between the EGR take-out portion 4c on the cylinder head 4 side and the lower surface 44 of the protruding portion on the surge tank 7 side, one end is connected to the EGR take-out portion 4c and the other end is on the lower surface 44 of the protruding portion. By connecting the surge tank 7, that is, the intake manifold 6 to the cylinder head 4
The EGR passage (recirculation passage)
An EGR pipe unit (intake system support member) 50 according to the present invention, which has 53 and 54 and is capable of circulating the EGR gas to the surge tank 7 side, is provided. As a result, the intake manifold 6 is satisfactorily held by the cylinder head 4, and a part of the exhaust gas can be circulated as EGR gas in the surge tank 7, that is, in the intake system as shown by the solid line arrow in FIG. . Then, part of the unburned fuel in the exhaust gas is burned again in the combustion chamber 3 to improve fuel efficiency, and carbon dioxide with a large heat capacity in the exhaust gas is returned to the combustion chamber 3. The combustion temperature drops,
The generation of harmful NOx is suppressed.

Now, referring to FIG. 2, there is shown a front view of the EGR pipe unit 50. Hereinafter, referring to FIG. 2 together with FIG. 1, the structure and operation of the EGR pipe unit 50 according to the present invention will be described. explain in detail. EGR
The pipe unit 50 is mainly formed integrally with the tubular EGR pipe portion 52 having the EGR passages 53 and 54 therein, and extending obliquely away from the approximate center of the EGR pipe portion 52. The beam 55 and a reinforcing rib 55a integrally connecting the beam 55 and the EGR pipe portion 52. The EGR pipe unit 50 is made of metal such as cast iron and die cast aluminum.

A flange 52a is formed at one end of the EGR pipe portion 52, and the flange 52a is firmly fixed to the EGR take-out portion 4c by a fastener such as a bolt B. On the other hand, a flange 52b is formed horizontally at the other end of the EGR pipe portion 52, and the flange 52b is firmly fixed to the lower surface 44 of the protruding portion 40 of the protruding portion 40 by a fastener such as a bolt B. There is.

Further, a flange 56 is formed at the tip of the beam 55 separated from the EGR pipe portion 52, and this flange 56 is also firmly fixed to the side surface of the cylinder head 4 by a fastener such as a bolt B. Has been done. Therefore, in the EGR pipe unit 50, the flanges 52a and 52b on both sides of the EGR pipe portion 52 are firmly fixed to the cylinder head 4 side and the surge tank 7 side by the bolts B and the flange 56 is also fixed by the bolts B and the like. By being firmly fixed to the cylinder head 4, it functions as a supporting member extremely well. That is, since the EGR pipe portion 52 is formed in a tubular shape, the rigidity as the supporting member is sufficiently high only by fixing the EGR pipe portion 52.
Since 6 is fixed to the cylinder head 4, the supporting rigidity of the EGR pipe unit 50 is further increased due to the existence of the beam 55 and the rib 55a.

Referring to FIGS. 1 and 2, of the EGR passage 53 and the EGR passage 54 in the EGR pipe portion 52, the EG
The R passage 53 can communicate with the internal passage 39 of the cylinder head 4, and the EGR passage 54 can communicate with the internal passage 42 in the protrusion 40. A flange 58 is formed substantially horizontally at a substantially central portion of the EGR pipe portion 52, and an EGR valve (recirculation gas control valve) 64 is bolted to the flange 58 in a suspended state. It is attached by fasteners such as.

Referring to FIG. 3, there is shown a top view of the EGR pipe unit 50 viewed from the direction of arrow A in FIG. 2. As shown in FIG.
The flange 58 at the substantially central portion is formed with an opening 53a in which the EGR passage 53 opens downward and an opening 54a in which the EGR passage 54 opens downward. Therefore, the EGR valve 64 has the openings 53a, 54
It is attached to the flange 58 so that a and the input / output port of the EGR valve 64 are aligned with each other. As a result, the EGR passage 53 and the EGR passage 54 can be connected and disconnected via the EGR valve 64, and the flow rate of EGR gas flowing through the EGR passages 53 and 54 from the internal passage 39 to the internal passage 42 can be adjusted. Has been done.

The EGR valve 64 will be described in more detail. The EGR valve 64 is configured as a flow rate control valve whose opening changes according to the rotation amount of the step motor 64a, and the step motor 64a is electrically connected to the ECU 70. ing. Therefore, the step motor 64a rotates in response to the drive signal from the ECU 70, which causes the EG
The opening degree of the R valve 64 is appropriately changed so that the EGR passage 53,
The flow rate of EGR gas flowing through 54 can be adjusted. The drive signal at this time is determined based on the information from the various sensors 72. As the sensor applied at this time, in addition to the air flow sensor, the warm-up state of the engine 1 may be the engine cooling water. There is a water temperature sensor (not shown) that detects the temperature.

By the way, the EGR valve 64 is attached to the substantially central portion of the EGR pipe portion 52 as described above. As described above, the EGR valve 64 is not provided on the cylinder head 4 side or the surge tank 7 side, and the EGR pipe portion 5 is not provided.
The reason why it is provided in the approximate center of 2 is as follows. EG
The reason why the R valve 64 is not provided on the cylinder head 4 side is that the durability of the step motor 64a of the EGR valve 64 is not so high in a high temperature environment.
This is because the valve 64 cannot be brought close to the cylinder head 4.

Further, if the EGR valve 64 is provided on the cylinder head 4 side, it takes time until the EGR gas reaches the intake system after the EGR valve 64 is opened, and the flow rate of the EGR gas is switched. When
This is because a so-called response delay may occur. on the other hand,
The reason why the EGR valve 64 is not provided on the surge tank 7 side is
Normally, when the EGR gas passes through the EGR pipe section 52 from the cylinder head 4 side toward the surge tank 7 side, EG
Although the temperature of the R gas decreases, when the temperature of the EGR gas decreases, for example, liquid components (eg, unburned fuel) and soot in the EGR gas that have been vaporized or atomized in a high temperature state are liquefied or large grains. It is based on the fact that the EGR valve 64 may become solidified and adhere to the inner wall of the EGR valve 64, which may cause clogging of the internal passage of the EGR valve 64, making it difficult to control the flow rate of a small amount of EGR gas.

Further, as described above, the PCV pipe 28
The blow-by gas is supplied into the surge tank 7 via the. The blow-by gas also contains a part of the lubricating oil (hereinafter referred to as oil mist) scattered in the cylinder head chamber. A part of this oil mist is again sucked into the combustion chamber 3 through the surge tank 7, while a part of the oil mist is, for example, the EGR valve 6
This is based on the fact that the valve 4 also enters the internal passage 42 when the valve is closed.

That is, when the EGR valve 64 is attached near the protrusion 40 on the surge tank 7 side, a part of the oil mist that has entered the internal passage 42 is discharged from the EGR valve 6.
4 adheres to the inner wall of the EGR valve 4 and may cause the EGR valve 64 to be clogged. Therefore, since the EGR pipe portion 52 has sufficient strength and is not bent by the weight of the EGR valve 64, the EGR valve 64 is attached to a substantially central portion of the EGR pipe portion 52. Thus, the EGR valve 64 is not too close to the cylinder head 4 to be damaged by heat, is not too close to the surge tank 7 to cause clogging of the internal passage, and even if the flow rate of the EGR gas is small. Circulation control of EGR gas to the intake system can always be favorably performed. In particular, under today's demand for reduction of NOx, the EGR valve 64 tends to be large-sized and high-performance so that the amount of EGR gas can be appropriately controlled in a wide range. Even with such an EGR valve 64, it is possible to always finely and appropriately control the flow rate of the EGR gas and circulate it in the intake system.

As is apparent from FIG. 1 or 2, the portion of the EGR pipe portion 52 closer to the surge tank 7 than the flange 58, that is, the EGR passage 54, is bent in a substantially S shape in the vertical direction. . In other words, the EGR passage 54 that has once extended downward near the surge tank 7 is
The pipe portion 52 is directed upward as it goes toward the central portion thereof, and therefore the EGR passage 5 in the flange 58 is formed.
The position of the opening 54a of No. 4 is higher than the position of the EGR passage 54 on the surge tank 7 side. This is a means for preventing the oil mist from reaching the EGR valve 64 as much as possible when part of the oil mist in the blow-by gas enters the internal passage 42 as described above. Hereinafter, the operation of the EGR passage 54 bent in a substantially S shape will be described.

Referring to FIG. 4, for example, the EGR valve 6
When 4 is in the valve closed state, the blow-by gas is supplied into the surge tank 7, and a schematic diagram of a situation in which part of the oil mist M in the blow-by gas has entered the internal passage 42 is shown. That is, as shown in the figure, a part of the oil mist M in the blow-by gas normally drops along the wall surface of the internal passage 42, and the oil mist M becomes a drop D and reaches the EGR passage 54. , This EGR pipe unit 5
At 0, since the EGR passage 54 is curved in a substantially S shape in the vertical direction, the droplet D is stored in the lowest portion 54b of the EGR passage 54, whereby the droplet D, that is, the lubricating oil, is stored in the EGR valve. 64 is not reached. Therefore, the oil mist M in the blow-by gas, that is, the lubricating oil is more preferably prevented from adhering to the inner wall surface of the EGR valve 64, and the function of the EGR valve 64 is more preferably maintained.

The lubricating oil accumulated in the lowest portion 54b of the EGR passage 54 is returned to the surge tank 7 in the form of oil mist together with the EGR gas when the EGR valve 64 is opened. It is sent to and burned. As described above in detail, according to the exhaust gas recirculation system for an internal combustion engine of the present invention, the E according to the present invention
The GR pipe unit (intake system support member) 50 includes an EGR pipe section 52 that performs exhaust gas recirculation, and
In addition to the EGR pipe portion 52 having a high rigidity, the EGR pipe portion 52 has a beam 55 and a rib 55a and is configured to function as a support member of the intake manifold 6.

Therefore, in recent years, the surge tank 7, that is, the intake manifold 6 tends to be large in size in order to improve the intake efficiency due to the increase of the exhaust amount and the supercharging effect. A support member is required to prevent vibration, etc., but in the case of the engine 1 having the exhaust gas recirculation function, by providing the EGR pipe unit 50 of the present invention, a separate support member for the intake manifold 6 is provided. Without
Supporting the intake manifold 6 well, the engine 1
The vibration of the intake manifold 6 at the time of operation, etc. can be suppressed well, and the engine 1 can be downsized, and the cost can be saved by reducing the number of parts.
As a result, it becomes possible to save space in the engine room of the vehicle, which tends to become narrower as the intake manifold 6 becomes larger, and the maintainability of the engine 1 also improves.

Further, the EGR pipe unit 50 of the present invention
Since the EGR pipe section 52 has rigidity, EG
The R valve 64 is attached to the approximate center of the EGR pipe portion 52. Therefore, it is possible to bring the EGR valve 64 close to the cylinder head 4 so as not to cause heat damage to the EGR valve 64 or cause a response delay, and
It is possible to bring the EGR valve 64 close to the surge tank 7 and prevent soot, lubricating oil, etc. from adhering to the inside of the EGR valve 64. Therefore, the function of the EGR valve 64 is appropriately maintained and the EGR gas is always kept properly. It becomes possible to control.

Further, the EGR pipe unit 5 of the present invention
At 0, the portion of the EGR pipe portion 52 on the surge tank 7 side, that is, the EGR passage 54 is curved in a substantially S shape in the vertical direction. Therefore, even if a part of the oil mist in the blow-by gas enters the internal passage 42, the oil mist that has become a drop is collected in the lowest portion 54b of the EGR passage 54, so that the lubricating oil is transferred to the EGR valve 64 as much as possible. The EGR valve 6 can be prevented from reaching the inner wall of the EGR valve 64 almost certainly by preventing the lubricating oil from adhering to the inner wall of the EGR valve 64.
The function of 4 can be maintained more preferably.

In the above embodiment, the case where the intake port 2 extends vertically inside the cylinder head 4 and the intake manifold 6 becomes relatively large accordingly is explained. The internal combustion engine may have a normal structure in which the intake port extends horizontally inside the cylinder head and the intake manifold is connected to the side surface of the cylinder head.

Further, the shapes of the beam 55 and the rib 55a are not limited to the above, but for example, EGR
When the pipe portion 52 is made of cast iron, the reinforcing effect may be enhanced by increasing the wall thickness of the EGR pipe portion 52 itself without providing the beam 55 and the rib 55a.
However, in this case, considering the action of the moment generated by the vibration of the EGR valve 64, the EGR pipe portion 52
It is necessary to design the wall thickness of the so as to have sufficient strength to withstand this moment.

[0043]

As described above in detail, the first aspect of the present invention is as follows.
According to the exhaust gas recirculation device for an internal combustion engine, one end of the intake system support member is connected to the internal combustion engine body including the recirculation gas outflow portion, and the other end includes the recirculation gas inflow portion. The intake system support member is provided with a recirculation passage that guides the recirculation gas from the recirculation gas outflow portion to the recirculation gas inflow portion. It can be favorably supported by the main body, and at the same time, the recirculation gas which is a part of the exhaust gas can be circulated favorably in the intake system of the internal combustion engine.
Therefore, it is not necessary to separately provide a support member for supporting the intake system member of the internal combustion engine, and the internal combustion engine can be downsized.
It is possible to reduce the cost and space of the vehicle engine room. Also, the oil mist (lubricating oil) in the blow-by gas returned to the intake system forms droplets on the wall surface of the recirculation passage and enters the recirculation passage. Can be stored in
Lubricating oil is placed at a lower position than the recirculation gas inlet
As described above, it is possible to make it difficult to enter the recirculation gas control valve provided in the recirculation passage, and it is possible to preferably prevent contamination of the recirculation gas control valve due to adhesion of lubricating oil. Further, the oil accumulated at the bottom position of the recirculation passage can be returned to the intake system of the internal combustion engine again together with the recirculation gas.

Further, according to the exhaust gas recirculation device for an internal combustion engine of claim 2 , the recirculation gas control valve is attached to an intermediate portion of the recirculation passage, so that the recirculation gas control valve causes heat damage to the internal combustion engine. In addition to making it harder to receive, before the temperature of the recirculation gas decreases and the soot in the recirculation gas becomes large, the recirculation gas is passed through the recirculation gas control valve to prevent soot from entering the recirculation gas control valve. It is possible to preferably prevent the recirculation gas control valve from being contaminated due to adhesion. Furthermore, since the recirculation gas control valve is located away from the intake system, it is difficult to let the oil mist (lubricating oil) in the blow-by gas enter the recirculation gas control valve, and the recirculation gas control valve is lubricated. It is also possible to preferably prevent stains and the like due to the adhesion of oil.

[0045]

Further, according to the exhaust gas recirculation system for an internal combustion engine of claim 3 , when the recirculation gas control valve can control the flow rate of the recirculation gas over a wide range, the recirculation gas control valve is usually used. However, it is difficult to properly control the flow rate of the recirculation gas because the valve body is contaminated, but by using the exhaust gas recirculation device of the present invention, the recirculation gas control valve is large and Even if the flow rate of the circulating gas can be adjusted over a wide range, the control of the flow rate of the recirculating gas can be suitably maintained by preventing the valve body of the recirculating gas control valve from being contaminated.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an overall configuration of an exhaust gas recirculation device for an internal combustion engine of the present invention.

FIG. 2 is a side view showing an EGR pipe unit as an intake system support member according to the present invention.

FIG. 3 is a top view of the EGR pipe unit viewed from the direction of arrow A in FIG.

FIG. 4 is a diagram illustrating an operation of the EGR pipe unit when an oil mist in blow-by gas enters.

[Explanation of symbols]

1 engine 4 cylinder head 4c EGR outlet (recirculated gas outlet) 6 Intake manifold (intake system member) 7 surge tank 11 Throttle valve 26 PCV valve 28 PCV pipe 40 Projection 44 Bottom surface of protruding part (recirculation gas inflow part) 50 EGR pipe unit (intake system support member) 52 EGR pipe section 53 EGR passage (recirculation passage) 53a opening 54 EGR passage (recirculation passage) 54a opening 54b lowest part 55 beams 55a Reinforcing rib 64 EGR valve (recirculation gas control valve)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaya Hasumi 4-21-1, Shimomaruko, Ota-ku, Tokyo Within Sanryo Engineering Co., Ltd. (72) Inventor Takahiro Seichi 4-21-1, Shimomaruko, Ota-ku, Tokyo Sanritsu Automobile Engineering Co., Ltd. (56) Reference JP-A-8-218941 (JP, A) JP-A-9-105338 (JP, A) JP-A-9-303225 (JP, A) JP-A-7 -42625 (JP, A) Actual Open 4-123359 (JP, U) Actual Open 61-175558 (JP, U) Actual Public 7-8805 (JP, Y2) Actual Public 60-34764 (JP, Y1 ) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02M 25/07 580 F02M 25/07 520 F02M 25/07 570 F02M 35/10 F01M 13/00

Claims (3)

(57) [Claims] 1. A recirculation gas outflow portion, which is provided in an internal combustion engine body and takes out a part of exhaust gas derived from an exhaust system of the internal combustion engine as recirculation gas, and an intake system member of the internal combustion engine, A recirculation gas inflow part for inflowing the recirculation gas, and an intake system member of the internal combustion engine having one end connected to the internal combustion engine body including the recirculation gas outflow part and the other end including the recirculation gas inflow part An intake system support member connected to the recirculation gas, and a recirculation passage formed in the intake system support member for guiding the recirculation gas from the recirculation gas outflow part to the recirculation gas inflow part. A recirculation gas control valve for adjusting the flow rate of the recirculation gas is provided in the passage at a valve opening position of the recirculation gas inflow portion.
The recirculation passage is mounted so as to be disposed at a lower position, and at least a portion of the recirculation passage between the recirculation gas inflow portion and the valve opening position of the recirculation gas control valve is recirculated. An exhaust gas recirculation system for an internal combustion engine, wherein a bottom surface position of the passage has a passage portion set lower than a valve opening position of the recirculation gas control valve. Wherein characterized in that said recirculation gas control valve is installed in the middle portion of the recirculation passage, exhaust gas recirculation system for an internal combustion engine according to claim 1, wherein. Wherein said recirculation gas control valve, characterized in that said adjustable over the flow rate of the recycle gas in a wide range, exhaust gas recirculation apparatus according to claim 1 or 2 internal combustion engine according.